Endeavors have been made to manually expand an end region of metal tubing but such efforts have not been entirely satisfactory. Such devices comprise manually operated screw threaded means in which a plurality of expanding fingers are engaged by two cones, one of which is mounted on a shaft, and the opposite end of the shaft threaded to receive a nut. In using such a device the operator telescopes an end region of a tube to be expanded onto the fingers and applies a wrench to the nut on the shaft to draw the cones toward one another and thereby expand the fingers.
The cone adjacent the open end of the tube moves the fingers outwardly more easily than the other cone so that when the nut is drawn up it is found that the end region of the tube is usually expanded a greater amount than the region of the tube adjacent the opposite cone so that the expanded portion is tapered and not circular cylindrical. Even with the use of substantial manual pressure, the expanded portion of the tube is of slightly tapered character with the larger diameter of the expansion at the open end of the tube. Furthermore in the use of such device there is no indexing means for determining the extent of movement of the cones in expanding a tube so that it is extremely difficult to duplicate the same amount of expansion of a succeeding tube or tubes.